Helical vent fluid bleeder



Jan. 4, 1944. I H. MCCURDY 2,338,347

HELICA'L VE'NT' FLUID BLEEDER I Original Filed July 9, 1958 AZ $20474 /77c(rrd Patented Jan. 4, 1944 UNI -(S A E ,PATENT OFFICE Howard McCurdy, ZWal1iut Park, Calif.

Original application July 9, 1938, Serial No.

218,376. Divided and this application November 30, 1940, Serial N0. 367,945

3 Claims: 101. 181-44) This invention is a noise and pressure wave control device for dissipating noise and wave pressure of various fluids passing in a conduit.

It is an object of the instant invention to provide an effective, simple, low-cost, practical and durable device for initially bleeding off the energy of a fluid under pressure and passing to atmospheric space in the most direct method, and also to then later dissipate the remaining volume of the fluid much of whose energy has been sliced off to atmosphere at the intake end of the device; herein generally called the bleeder.

A further object of the invention is to effect a balance of the initial bleeding off or stream slicing function; that is to have concurrent expansion of stream parts at diametrically opposite points along a helical system of venting slots in the conduit wall, and also to provide for balanced effect of the discharge of the main volume of the stream at a zone axially beyond the energy dissipation zone.

Another object is to provide for a more or less restricted escape capacity of the slots at the higher pressure end of the bleeder, that is individual capacity for outlet, and to provide for more voluminous discharge of each slot at the lower pressure end of the device.

The invention consists in certain advancements in this art as set forth in the ensuing disclosure and having, with the above, additional objects and advantages as hereinafter developed, and whose construction, combination, and details of means and the manner of operation will be made manifest in the following description of the herewith illustrative variants; it being understood that modifications, variations and adaptations may be resorted to within the spirit, scope and principle of the invention as it is more particularly claimed presently.

Figure 1 is a sectional elevation of a helical vent bleeder and Figure 2 is an end view of the outlet end thereof.

Figure 3 is an elevation of a form showing right and left hand pitched vent slots.

Figures 4, 5, 6 and 7 are fragmental, sectional elevations of various forms of contours for the slot lips.

Figure 8 is a detail of a recessed flange feature.

The present embodiment is a direct diffusing bleeder having a suitably elongate and preferably cylindrical shell or conduit 2 with an inlet end 3 suitably attachable to a given apparatus, such as the discharge pipe 4 of a combustion motor. It is desirable that each successive, pressure stimulated gas wave shall be subjected to a noise reduction reaction and at the same time the pressure wave will be allowed to proceed to an ultimate discharge in such a manner that the finally released pulsation will be substantially devoid of energy.

The longitudinal wall of the shell 2 is provided with preferably a plurality of sinuous edge radially venting slots 5--6 shown as of helical advance along the shell. The slots 5 and 6 are of equal helical pitch and start from diametrically opposite points so that these relative slots are, to the extent of their common lengths, at all points diametrically opposite each other with the result that a wave passing in the bore of the shell is subjected to a balanced slicing efiect as by the rear lip 8 of each of the slots.

Fig. 1 shows the intake end of the device as having four equispaced slots (annularly) and of equal helical pitch, and a feature is that for a considerable length these slots are narrow, from lip l to lip 8, so as to provide a restricted escape for that part of the exhausting stream of highest pressure and therefore energy.

It will be seen that the quadruple venting slots at the intake end of the shell, in the aggregate, will provide desired area to dissipate a considerable part of the gas stream having the highest energy. The residue of the stream may be effectually expanded through a lesser number of helical slots and therefore the outlet end of the shell is here shown with but two diametrically opposite helical slots; being the continuation of slots 5 and 6; slots 5 and 6 being stopped well back from the far end of the shell.

A further feature of the invention is that the extended portions of slots 5 and 6 are each widened to their far ends to afford larger aggregate diffusion area for the passing lower pressure fluid stream. The slots 5 and 6 are shown as being of gradually widening form and this is preferably had by continuing the front lip 1 of the slots with the same angle of helical pitch as had at the start thereof while the opposite and slicingeifect lip 8 verges gradually away from the lip 1.

The terminal edge of the shell 2 is preferably a helix ill of equal pitch with that of the lip l of the relative slot; being in fact a continuation of the lip from the point where the slot ends.

The shell 2 may be built of a plurality of helical, right-line wall ribbons 2 each suitably edgespaced to form the Venting slots and they are here fixed rigidly in cylindric form as by external, longitudinal fin-like flanges I2.

Fig. 1 shows the slot lips as plain edges of the ribbons 2' but in Fig. 4 both edges I! and I8 are out-turned and converged relatively. In Fig. 5 there is provided one plain edge or lip 8 and opposite to it an upwardly flared lip ll. In Fig. 6 the lips 24 and 25 are parallel and both upwardly flared. Fig. '7 shows the lower lip ll flared outwardly from the shell and the upper, slicing lip flangedinwardly and downwardly at IS.

The several fixing flanges [2 may have their inner edges opposite the slots 5 and 6 slightly out back at I2 to avoid undue resistance to gas expansion; Fig. 8.

In some adaptations the slots 5 and 6 may, instead of being parallel helical embodiments, be one or more of right-hand pitch while others may be left-hand; the rights and the lefts being in diametrically opposite relation. Figure 3 shows this modification.

It is understood that one or more of the vents having diverging width of aperture may be em- ..ployed in a shell.

An arrangement of an odd number of the helical vents may not show a diametrically opposite system but they would effect a. balance in slicing function.

Reference is made to McCurdy U. S, Patent No. 2,247,130 as not claiming but showing in Fig. 1, the feature of a plurality of oppositely arranged helical vents of the same direction of pitch.

What is claimed is:

1. A :fiuid expansion silencer she'll comprising a tube having helical vents along its length and parts of which gradually increase in width toward the outlet end of the shell,

2. A silencer of the class described and comprising a flow tube having helical vents provided with lip flanges which are oblique as to the axis of the helix.

3. .A fluid expansion silencer including a cylindric, smooth wall conduit tube having a plurality of continuous, helical vents, from its chamber, in balanced venting relation, and in which portions of said vents toward the tube outlet increase gradually in width toward the tube outlet end.

HOWARD McCURDY. 

